U.S. patent number 10,093,593 [Application Number 15/618,016] was granted by the patent office on 2018-10-09 for use of catalyst to adjust product distributions in mto process.
This patent grant is currently assigned to UOP LLC. The grantee listed for this patent is UOP LLC. Invention is credited to Andrea G. Bozzano, Thulasidas Chellppannair, Gregory A. Funk, Nicholas J. Schoenfeldt, Wolfgang A. Spieker, Bipin V. Vora.
United States Patent |
10,093,593 |
Funk , et al. |
October 9, 2018 |
Use of catalyst to adjust product distributions in MTO process
Abstract
A process is presented for generating light olefins with the
methanol to olefins process from a combination of catalysts. The
process controls the product distribution for ethylene, propylene
and butylenes, to enable shifting of the product distribution. The
process includes passing a second catalyst to a reactor while the
process is on-going.
Inventors: |
Funk; Gregory A. (Carol Stream,
IL), Bozzano; Andrea G. (Northbrook, IL), Schoenfeldt;
Nicholas J. (Chicago, IL), Chellppannair; Thulasidas
(Cave Creek, AZ), Spieker; Wolfgang A. (Glenview, IL),
Vora; Bipin V. (Naperville, IL) |
Applicant: |
Name |
City |
State |
Country |
Type |
UOP LLC |
Des Plaines |
IL |
US |
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Assignee: |
UOP LLC (Des Plaines,
IL)
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Family
ID: |
56108347 |
Appl.
No.: |
15/618,016 |
Filed: |
June 8, 2017 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20170297973 A1 |
Oct 19, 2017 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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PCT/US2015/063654 |
Dec 3, 2015 |
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62090683 |
Dec 11, 2014 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C07C
1/20 (20130101); C07C 6/04 (20130101); C07C
4/02 (20130101); C07C 1/20 (20130101); C07C
11/04 (20130101); C07C 1/20 (20130101); C07C
11/06 (20130101); C07C 6/04 (20130101); C07C
11/06 (20130101); Y02P 30/40 (20151101); Y02P
30/20 (20151101); Y02P 30/42 (20151101); C07C
2529/85 (20130101) |
Current International
Class: |
C07C
1/20 (20060101); C07C 6/04 (20060101); C07C
4/02 (20060101) |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Pregler; Sharon
Parent Case Text
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a Continuation of copending International
Application No. PCT/US2015/063654 filed Dec. 3, 2015, which
application claims priority from U.S. Provisional Application No.
62/090,683 filed Dec. 11, 2014, the contents of which cited
applications are hereby incorporated by reference in their
entirety.
Claims
The invention claimed is:
1. A process for the production of light olefins comprising:
passing a first catalyst feed comprising a first catalyst to an MTO
reactor wherein the MTO reactor in a fluidized bed reactor system;
passing an oxygenate stream to an MTO reactor to generate an
effluent stream comprising olefins, and having a propylene to
ethylene product distribution, for converting oxygenates to
olefins; sampling the effluent stream to measure the propylene to
ethylene to butylenes product distribution; continuing the first
catalyst feed to the MTO reactor until a second olefins product
distribution is desired; discontinuing passing the first catalyst
feed to the MTO reactor; passing a second catalyst feed comprising
a second catalyst to the MTO reactor; sampling the effluent stream
to measure the propylene to ethylene to butylenes product
distribution; and continuing the second catalyst feed to the MTO
reactor until a new propylene to ethylene to butylenes product
distribution is achieved.
2. The process of claim 1 further comprising passing the effluent
stream to a light olefins recovery unit to generate an ethylene
stream, a propylene stream, and a heavies stream.
3. The process of claim 2 further comprising: passing the heavies
stream to an olefins cracking unit to generate an olefins cracking
effluent stream; and passing the olefins cracking effluent stream
to the light olefins recovery unit.
4. The process of claim 2 further comprising generating a butenes
stream in the light olefins recovery unit.
5. The process of claim 4 further comprising passing a portion of
the ethylene stream and a portion of the butenes stream to a
metathesis unit to generate a methathesis stream comprising
propylene.
6. A process producing olefins in a methanol to olefins conversion
process, comprising: splitting an oxygenate feed into two portions;
passing a first portion of the oxygenate feed to a first MTO
reactor comprising a first catalyst to generate a first MTO reactor
effluent; passing a second portion of the oxygenate feed to a
second MTO reactor comprising a second catalyst to generate a
second MTO reactor effluent; combining the first reactor effluent
and the second reactor effluent to generate a combined effluent
stream; sampling the combined effluent stream to measure the
propylene to ethylene to butylenes product distribution; and
adjusting the splitting of the oxygenate feed into two portions to
further adjust the combined product stream.
7. The process of claim 6 further comprising passing the combined
effluent stream to a DME recovery unit to generate an olefins
process stream and a DME recycle stream.
8. The process of claim 7 further comprising passing the olefins
process stream to a light olefins recovery unit to generate an
ethylene stream, a propylene stream, and a heavies stream.
Description
FIELD OF THE INVENTION
The present invention relates to the conversion of oxygenates to
olefins. In particular, this invention relates to the conversion of
methanol to light olefins.
BACKGROUND
The light olefins serve as feed materials for the production of
numerous chemicals. Light olefins have traditionally been produced
through the processes of steam or catalytic cracking. The limited
availability and high cost of petroleum sources, however, has
resulted in a significant increase in the cost of producing light
olefins from such petroleum sources.
The search for alternative materials for light olefin production
has led to the use of oxygenates such as alcohols and, more
particularly, to the use of methanol, ethanol, and higher alcohols
or their derivatives. The oxygenates are often produced from more
plentiful sources of raw materials, such as conversion of natural
gas to alcohols, or the production of oxygenates from coal.
Molecular sieves such as microporous crystalline zeolite and
non-zeolitic catalysts, particularly silicoaluminophosphates
(SAPO), are known to promote the conversion of oxygenates to
hydrocarbon mixtures, particularly hydrocarbon mixtures composed
largely of light olefins.
The amounts of light olefins resulting from such processing can be
further increased by reacting, i.e., cracking, heavier hydrocarbon
products, particularly heavier olefins such as C.sub.4 and C.sub.5
olefins, to light olefins. For example, commonly assigned, U.S.
Pat. No. 5,914,433 to Marker, the entire disclosure of which is
incorporated herein by reference, discloses a process for the
production of light olefins comprising olefins having from 2 to 4
carbon atoms per molecule from an oxygenate feedstock. The process
comprises passing the oxygenate feedstock to an oxygenate
conversion zone containing a metal aluminophosphate catalyst to
produce a light olefin stream. A propylene and/or mixed butylene
stream is fractionated from said light olefin stream and cracked to
enhance the yield of ethylene (C.sub.2H.sub.4) and propylene
(C.sub.3H.sub.6) products. This combination of light olefin product
and propylene and butylene cracking in a riser cracking zone or a
separate cracking zone provides flexibility to the process which
overcomes the equilibrium limitations of the aluminophosphate
catalyst. In addition, the invention provides the advantage of
extended catalyst life and greater catalyst stability in the
oxygenate conversion zone.
With the continued demand for light olefins, there is still a
demand for further improvements that will result in increased
yields, or reductions in processing costs, or equipment costs.
SUMMARY
While the following is described in conjunction with specific
embodiments, it will be understood that this description is
intended to illustrate and not limit the scope of the preceding
description and the appended claims.
A first embodiment of the invention is a process producing olefins
in a methanol to olefins conversion process, comprising passing a
catalyst feed combination to an MTO reactor comprising at least two
different types of catalyst to the MTO reactor in a fluidized bed
reactor system; passing an oxygenate stream to an MTO reactor, for
converting oxygenates to olefins, to generate an effluent stream
comprising olefins, and having an olefin product distribution;
sampling the effluent stream to measure the propylene to ethylene
to butylenes product distribution; and adjusting the catalyst feed
combination to the MTO reactor. An embodiment of the invention is
one, any or all of prior embodiments in this paragraph up through
the first embodiment in this paragraph wherein the MTO reactor
generates a catalyst effluent stream, further comprising passing
the catalyst effluent stream to a catalyst regenerator to generate
a regenerated catalyst stream. An embodiment of the invention is
one, any or all of prior embodiments in this paragraph up through
the first embodiment in this paragraph further comprising passing a
portion of the regenerated catalyst stream to a storage system. An
embodiment of the invention is one, any or all of prior embodiments
in this paragraph up through the first embodiment in this paragraph
further comprising passing one type of catalyst from a first
catalyst storage unit to the MTO reactor. An embodiment of the
invention is one, any or all of prior embodiments in this paragraph
up through the first embodiment in this paragraph further
comprising passing the effluent stream to a dewatering column to
generate a dewatered stream comprising light olefins. An embodiment
of the invention is one, any or all of prior embodiments in this
paragraph up through the first embodiment in this paragraph further
comprising passing the dewatered stream to a compressor to generate
a compressed process stream. An embodiment of the invention is one,
any or all of prior embodiments in this paragraph up through the
first embodiment in this paragraph further comprising passing the
compressed process stream to a DME recovery unit to generate a DME
effluent stream comprising olefins and a DME recycle stream
comprising DME. An embodiment of the invention is one, any or all
of prior embodiments in this paragraph up through the first
embodiment in this paragraph further comprising passing the
effluent stream to a light olefins recovery unit to generate an
ethylene product stream, a propylene product stream and a heavies
stream. An embodiment of the invention is one, any or all of prior
embodiments in this paragraph up through the first embodiment in
this paragraph further comprising passing the heavies stream to an
olefin cracking unit to generate an olefin cracking process stream
comprising light olefins; and passing the olefins process stream to
the light olefins recovery unit. An embodiment of the invention is
one, any or all of prior embodiments in this paragraph up through
the first embodiment in this paragraph further comprising passing a
first catalyst feed comprising a first catalyst to a catalyst
mixing unit; passing a second catalyst feed comprising a second
catalyst to the catalyst mixing unit to generate the catalyst feed
combination; and passing the catalyst feed combination to the MTO
reactor. An embodiment of the invention is one, any or all of prior
embodiments in this paragraph up through the first embodiment in
this paragraph further comprising operating the light olefins
recovery unit to generate a butene product stream. An embodiment of
the invention is one, any or all of prior embodiments in this
paragraph up through the first embodiment in this paragraph further
comprising passing a portion of the ethylene product stream and a
portion of the butene product stream to a metathesis reactor to
generate a propylene stream and a by-products stream.
A second embodiment of the invention is a process for the
production of light olefins comprising passing a first catalyst
feed comprising a first catalyst to an MTO reactor wherein the MTO
reactor in a fluidized bed reactor system; passing an oxygenate
stream to an MTO reactor to generate an effluent stream comprising
olefins, and having a propylene to ethylene product distribution,
for converting oxygenates to olefins; sampling the effluent stream
to measure the propylene to ethylene to butylenes product
distribution; continuing the first catalyst feed to the MTO reactor
until a second olefins product distribution is desired;
discontinuing passing the first catalyst feed to the MTO reactor;
passing a second catalyst feed comprising a second catalyst to the
MTO reactor sampling the effluent stream to measure the propylene
to ethylene to butylenes product distribution; and continuing the
second catalyst feed to the MTO reactor until a new propylene to
ethylene to butylenes product distribution is achieved. An
embodiment of the invention is one, any or all of prior embodiments
in this paragraph up through the second embodiment in this
paragraph further comprising passing the effluent stream to a light
olefins recovery unit to generate an ethylene stream, a propylene
stream, and a heavies stream. An embodiment of the invention is
one, any or all of prior embodiments in this paragraph up through
the second embodiment in this paragraph further comprising passing
the heavies stream to an olefins cracking unit to generate an
olefins cracking effluent stream; and passing the olefins cracking
effluent stream to the light olefins recovery unit. An embodiment
further comprising generating a butenes stream in the light olefins
recovery unit. An embodiment of the invention is one, any or all of
prior embodiments in this paragraph up through the second
embodiment in this paragraph further comprising passing a portion
of the ethylene stream and a portion of the butenes stream to a
metathesis unit to generate a methathesis stream comprising
propylene.
A third embodiment of the invention is a process producing olefins
in a methanol to olefins conversion process, comprising splitting
an oxygenate feed into two portions; passing a first portion of the
oxygenate feed to a first MTO reactor comprising a first catalyst
to generate a first MTO reactor effluent; passing a second portion
of the oxygenate feed to a second MTO reactor comprising a second
catalyst to generate a second MTO reactor effluent; combining the
first reactor effluent and the second reactor effluent to generate
a combined effluent stream; sampling the combined effluent stream
to measure the propylene to ethylene to butylenes product
distribution; and adjusting the splitting of the oxygenate feed
into two portions to further adjust the combined product stream. An
embodiment of the invention is one, any or all of prior embodiments
in this paragraph up through the third embodiment in this paragraph
further comprising passing the combined effluent stream to a DME
recovery unit to generate an olefins process stream and a DME
recycle stream. An embodiment of the invention is one, any or all
of prior embodiments in this paragraph up through the third
embodiment in this paragraph further comprising passing the olefins
process stream to a light olefins recovery unit to generate an
ethylene stream, a propylene stream, and a heavies stream.
Without further elaboration, it is believed that using the
preceding description that one skilled in the art can utilize the
present invention to its fullest extent and easily ascertain the
essential characteristics of this invention, without departing from
the spirit and scope thereof, to make various changes and
modifications of the invention and to adapt it to various usages
and conditions. The preceding preferred specific embodiments are,
therefore, to be construed as merely illustrative, and not limiting
the remainder of the disclosure in any way whatsoever, and that it
is intended to cover various modifications and equivalent
arrangements included within the scope of the appended claims.
In the foregoing, all temperatures are set forth in degrees Celsius
and, all parts and percentages are by weight, unless otherwise
indicated.
Other objects, advantages and applications of the present invention
will become apparent to those skilled in the art from the following
detailed description and drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 product distribution for three catalysts;
FIG. 2 shows a first embodiment of the process;
FIG. 3 shows a second embodiment of the process; and
FIG. 4 shows a third embodiment.
DETAILED DESCRIPTION
The production of light olefins, ethylene and propylene, are
important precursors for products today, most notably, the
principal products are polyethylene and polypropylene. The source
of these precursors has been mainly from the cracking of naphtha.
Increasingly, other sources for the production of light olefins is
sought due to cost considerations and availability of raw
materials. Oxygenate, notably methanol, can be converted and is
increasingly being used. Methanol can be generated from several
sources, including natural gas and coal.
The methanol to olefin (MTO) process has been successfully
commercialized. U.S. Pat. No. 6,303,839 presents an integrated
MTO-olefin cracking process. The oxygenate feedstock is
catalytically converted over a silicoaluminophosphate (SAPO)
catalyst. The increase in light olefin production is also described
in U.S. Pat. No. 7,317,133 wherein the production of heavier
olefins are directed to an olefin cracking reactor to generate a
process stream comprising light olefins. The olefin cracking
process utilizes a different catalyst from a family of crystalline
silicate having an WI or MEL. Examples of these catalysts include
ZSM-5 or ZSM-11.
Additional process developments continue to be generated, such as
U.S. Pat. No. 7,568,016 that integrates the MTO with an ethylene
dimerization process and metathesis process for increasing the
propylene yields. The dimerization process can also be used to
increase the heavier olefins for other purposes. U.S. Pat. No.
7,732,650 describes a process for the separation of butenes, along
with isomerization and metathesis reactions.
Processes are also developed that operate around control conditions
of the reactor, such as U.S. Pat. No. 6,137,022, wherein the
reaction zone is operated to contain a restricted amount of
catalyst, containing 15 volume percent or less, and operation is
controlled to limit conversion of the feedstock to between 80 and
99%.
Other aspects include controlling the process with modifications of
the catalyst, such as limiting the Si/Al2 ratio to between 0.10 and
0.32 as in U.S. Pat. No. 7,763,765.
While there are many similar patents that cover integrated MTO-OCP
process to maximize ethylene and propylene, none of these processes
has flexibility to control the Propylene to Ethylene (P/E) product
ratio. The P/E product ratio is largely determined by the MTO and
OCP reactor yields. A high P/E ratio, preferably more than 3 is
desirable due to the increased demand for propylene. Due to this
increase in demand for higher propylene over ethylene, it has been
discovered that changing the catalyst preference and increasing the
pressure substantially has changed not only the product ratios in
the MTO process, but the catalyst deactivation rate has been found
to decrease, thereby enabling longer cycle times and improved
economics.
The changing market for different light olefins leads chemical
producers to desire flexibility in changing the product
distributions. Typically, the control of the product distributions
is dictated by the methanol to olefins (MTO) conversion process,
and the particular catalyst for producing a given product
distribution. The product distribution can also be modified by some
downstream process, such as olefin cracking and metathesis.
The present invention provides for modifying the product
distribution through a blending of catalysts, wherein each catalyst
generates a different product distribution. FIG. 1 shows a product
distribution for three different catalysts: SAPO-18 with 1.5% Si,
SAPO-34 with 1.2% Si, and MTO-100 with 4.1% Si.
A process for producing olefins in a methanol to olefins conversion
process is shown in FIG. 2. The process includes passing a catalyst
feed combination 8 to an MTO reactor 10. The catalyst feed
combination comprises at least two different types of catalysts
that are stored in a catalyst storage vessel 20a. The MTO reactor
10 is a fluidized bed reactor system with the catalyst flowing
between the reactor 10 and a regenerator 30. An oxygenate stream 6
is passed to the MTO reactor, where it is converted to an effluent
stream 12 comprising olefins, and the effluent stream 12 has an
olefin product distribution. The effluent stream 12 is sampled to
measure the propylene to ethylene ratio. To adjust the propylene to
ethylene ratio, the catalyst feed 8 is adjusted to shift the
product distribution. A preferred oxygenate feed comprises alcohols
and ethers, with a more preferred oxygenate feed comprising
methanol.
The process further includes generating a catalyst effluent stream
14, wherein the catalyst effluent stream 14 is passed to a catalyst
regenerator 30 to generate a regenerated catalyst stream 32. The
process can further comprising passing a portion of the regenerated
catalyst stream 32 to a catalyst storage system, wherein the
catalyst storage system can comprise one or more catalyst storage
vessels 20a, b. The regenerator 30 includes an air source 34 for
combusting carbon deposits on the catalyst and generates a regen
gas effluent stream 36.
The process can include passing a first type of catalyst from a
first catalyst storage unit to the MTO reactor 10, and passing a
second type of catalyst from a second catalyst storage unit 20b to
the MTO reactor.
The process further includes passing the effluent stream 12 to a
dewatering column 40 to generate a dewatered stream 42 comprising
light olefins. The dewatered stream 42 is passed to a compressor 50
to generate a compressed process stream 52. The compressed process
stream 52 is passed to a dimethyl ether (DME) recovery unit 60 to
generate a DME effluent stream 62 comprising olefins and a DME
recycle stream 64 comprising dimethyl ether. The DME recycle stream
64 is mixed with the oxygenate feedstream 6 and passed back to the
MTO reactor 10.
The DME effluent stream 62 is passed to a light olefins recovery
unit 70 to generate an ethylene product stream 72, a propylene
product stream 74, and a heavies product stream 76. The process can
further include passing the heavies stream 76 to an olefin cracking
unit 80 to generate an olefin cracking process stream 82 comprising
light olefins. The olefins process stream 2 is separated in a
separation section 90 to generate a by-products stream 92 and a
light olefins stream 94. The light olefins stream 94 is passed to
the light olefins recovery unit 70.
The light olefins recovery unit 70 comprises several distillation
columns and other process equipment for separating the light
olefins into separate product streams.
The light olefins recovery unit 70 can be operated to generate a
butene product stream 78. The process can further include passing a
portion of the ethylene product stream 72 and a portion of the
butene product stream 78 to a metathesis reactor 100 to generate a
propylene stream 102 and a by-products stream 104.
The process can include passing a first catalyst feed comprising a
first catalyst to a catalyst mixing unit, passing a second catalyst
feed comprising a second catalyst to the catalyst mixing unit to
generate the catalyst feed combination, and then passing the
catalyst feed combination to the MTO reactor.
In one embodiment, the process includes passing a first catalyst
feed comprising a first catalyst to an MTO reactor, wherein the MTO
reactor is a fluidized bed reactor system. An oxygenate stream is
passed to the MTO reactor, operated at reaction conditions to
generate an effluent stream comprising olefins, and having a
product distribution containing a propylene to ethylene ratio. The
effluent stream is sampled to measure the propylene to ethylene
ratio. The first catalyst is continued to be fed to the MTO reactor
until a second product distribution is desired. The first catalyst
feed to the MTO reactor is discontinued. A second catalyst feed
comprising a second catalyst is fed to the MTO reactor to generate
a second MTO reactor effluent stream. the second effluent stream is
sampled, and the propylene to ethylene ratio is measured. The
second catalyst feed is continued until a new propylene to ethylene
product distribution is desired.
The process further includes passing the effluent stream to a light
olefins recovery unit to generate an ethylene stream, a propylene
stream and a heavies stream.
In one embodiment, the process, as shown in FIG. 3, is operated to
generate a high heavies content, wherein the heavies comprises C4+
olefins, relative to the ethylene content. The process includes
passing an oxygenate feedstream 6 to the MTO reactor 10 to generate
an effluent stream 12 comprising olefins, but with a relatively
high heavy olefin content. The effluent stream 12 is passed to the
dewatering column 40 to generate a dewatered stream 42. The
dewatered stream 42 is compressed to generate a compressed stream
52. The compressed stream 52 is processed to remove DME in a DME
recovery unit 60. to generate an olefins effluent stream 62.
The light olefins recovery unit 70 separates the olefins effluent
stream 62 into an ethylene stream 72, a propylene stream 74, a
heavies stream 76 comprising C5+ hydrocarbons, and an n-butenes
stream 78. The ethylene stream 72 and the n-butenes stream 78 are
passed to a metathesis unit 110 to generate a propylene stream 112
and a by-products stream 114.
In a third embodiment, the process for producing olefins from
oxygenates comprises utilizing fixed beds for the MTO reactors, as
shown in FIG. 4. The process includes splitting an oxygenate feed
104 into two portions 106 and 108. A first portion 106 is passed to
a first MTO reactor 110 having a first catalyst to generate a first
MTO reactor effluent stream 112. A second portion 108 is passed to
a second MTO reactor 120 having a second catalyst to generate a
second MTO reactor effluent stream 122. The first effluent stream
112 and the second effluent stream 122 are combined to form a
combined stream 124. The combined stream 124 can be sampled to
measure the propylene to ethylene product ratio. This provides
feedback to adjust the split of the oxygenate feedstream 106 into
two portions.
The combined stream 124 is passed to a dewatering column 130 to
generate a dewatered process stream 132. The dewatered process
stream 132 is passed to a compressor 140 to generate a compressed
process stream 142. The compressed process stream 142 is passed to
a DME recovery unit 150 to generate a DME olefins stream 152 and a
DME recycle stream 154. The DME recycle stream 154 is passed back
to the feed to the MTO reactors. The DME olefins stream 152 is
passed to a light olefins recovery unit 160 to generate an ethylene
stream 162, a propylene stream 164, a butene stream 166 and a
heavies stream 168.
While the two fluidized fixed bed MTO reactor system is shown for
utilizing two catalysts in two separate reactors, this can also be
operated as two fluidized bed reactor systems with each reactor
system utilizing a different catalyst. The two reactor system can
also allow for different operating conditions for the different
catalysts. This provides flexibility to optimize each reactor
separately. A pressure control valve can be utilized when combining
the two effluent streams from the two reactors.
Recent testing has demonstrated that different MTO catalysts give
very different yield patterns. This can be seen in FIG. 1 for three
different MTO catalysts. In a similar manner, changing the % Si in
an MTO catalyst can also shift the yield pattern.
Since the typical MTO process is based on a fluidized bed system,
as a catalyst is removed from a reactor, the reactor can be emptied
of that catalyst, and a second catalyst can be transported from a
separate catalyst storage vessel to replace the removed catalyst.
This provides for maintaining the catalysts as separate
components.
Table 1 shows the results based on laboratory yield data for the
conventional SAPO-34 catalyst and for a second catalyst, or SAPO-18
catalyst. The oxygenate used was methanol. Both are tested under
conditions of a temperature of 400.degree. C. and a methanol
partial pressure of 1.34 MPa. Columns 2 and 3 summarize the yields
for SAPO-34 without OCP and with OCP. The OCP is estimated from
simulations based on known operations. For the SAPO-34 the
propylene to ethylene (P/E) yields increased from 1.39 to 1.68.
Similarly, columns 4 and 5 summarize the yields for SAPO-18 without
and with OCP. The SAPO-18 results gave a P/E ratio of 3.25 and
3.55. As demand changes for propylene, or ethylene, the catalyst
can be changed, or combined to shift the yields according to
demand.
TABLE-US-00001 TABLE 1 Catalyst 1 SAPO-34 SAPO-34 SAPO-18 SAPO-18
Catalyst 1 Amount, % 100.00% 100.00% 100.00% 100.00% Catalyst 2 --
-- -- -- Catalyst 2 Amount, % 0.00% 0.00% 0.00% 0.00% OCP No Yes No
No Metathesis No No No No C2= 31.0% 34.9% 12.0% 19.8% C3= 43.0%
58.6% 39.0% 70.3% C4= 14.0% 0.0% 32.0% 0.0% C5+= 9.0% 0.0% 14.0%
0.0% MTO Other Byproducts 3.0% 3.0% 3.0% 3.0% OCP Byproducts 0.0%
3.5% 0.0% 6.9% Metathesis Byproducts 0.0% 0.0% 0.0% 0.0% C3=/C2=
1.39 1.68 3.25 3.55 Total 100.0% 100.0% 100.0% 100.0%
The process, when including metathesis increases the propylene
yields while sacrificing some ethylene. This may be desirable as
ethylene is of lower value than the propylene. The metathesis
process also utilizes some of the heavier components, in particular
butenes, which also have a lower value than propylene.
Table 2 shows the results of combining two catalysts in the process
of producing propylene. The table shows the yields of two catalysts
separately, and of a combination of the two catalysts. The relative
amounts of product can therefore be determined by adjusting the
relative amounts of the two different catalysts.
The process shows that adding some SAPO-34 to a SAPO-18 system
increases the propylene over either catalyst alone, when the
process includes metathesis. This is due to SAPO-18 having a lower
yield of ethylene and therefore not converting as much of the
heavier olefins to propylene. The addition of a relatively small
amount of SAPO-34 increases the yield of ethylene, which in turn is
passed to the metathesis reactor, and resulting in an increase in
the overall propylene yields.
TABLE-US-00002 TABLE 2 Catalyst 1 SAPO-34 SAPO-18 SAPO-18 Catalyst
1 Amount, % 100.00% 100.00% 94.05% Catalyst 2 -- -- SAPO-34
Catalyst 2 Amount, % 0.00% 0.00% 5.95% OCP Yes Yes Yes Metathesis
Yes Yes Yes C2= 25.5% 0.0% 0.0% C3= 69.2% 90.7% 94.0% C4= 0.0% 3.2%
0.0% C5+= 0.0% 0.0% 0.0% MTO Other Byproducts 3.0% 3.0% 3.0% OCP
Byproducts 1.4% 2.1% 2.1% Metathesis Byproducts 0.9% 0.9% 1.0%
C3=/C2= 2.71 #DIV/0! #DIV/0! Total 100.0% 100.0% 100.0%
While the invention has been described with what are presently
considered the preferred embodiments, it is to be understood that
the invention is not limited to the disclosed embodiments, but it
is intended to cover various modifications and equivalent
arrangements included within the scope of the appended claims.
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